This AI search glossary defines the terms you will meet when working on answer engine optimization (AEO), each in a sentence or two. Where a term has a deeper guide, the definition links to it.
Core concepts
Answer engine optimization (AEO)
The work of getting AI engines such as ChatGPT, Gemini and Google AI to name your brand when buyers ask them questions. See What is AEO?.
Generative engine optimization (GEO)
Another name for the same work as AEO. The two terms are used interchangeably.
Answer engine
An AI system that responds to a question with a written answer, often with sources, rather than a list of links. ChatGPT, Gemini, Google AI Overviews and Google AI Mode are examples.
AI Overviews
The AI-generated summary Google shows within its regular search results for some queries. See Google AI Overviews vs AI Mode.
AI Mode
Google's separate conversational search experience, with its own tab, where people can ask follow-up questions. See Google AI Overviews vs AI Mode.
Query fan-out
A technique Google describes for AI Overviews and AI Mode in which one question is turned into multiple related searches across subtopics and data sources, and the results are combined into one answer (Google Search Central).
Grounding
When a model checks outside sources, such as search results, before it answers instead of relying only on what it learned in training.
Zero-click search
A search where the buyer gets what they need from the results page or the answer and never visits a website.
Hallucination
A confident statement in an AI answer that is not true.
Non-deterministic
Not guaranteed to give the same result each time. OpenAI describes the content generated by its models this way (OpenAI), which is why one check of an AI answer proves little.
Prompts and tracking
Prompt
A full question in a buyer's words, tracked over time. It is the AEO version of a keyword. See How to choose the prompts to track.
Subcategory
A group of related prompts, such as "pricing and value," used to see where you win and lose by topic.
Baseline
Your results before you make any changes, used to measure later gains. See How to track your brand in AI answers.
Wording sensitivity
How much the exact phrasing of a question changes which brands an AI engine names. See Why AI answers change with wording.
Super prompt
A Verte prompt tracked in five wordings and rotated through five times of day, to show how much wording matters. See Super prompts.
Metrics
Mention
Any time an AI answer names your brand, linked or not.
Visibility
The share of checks in which your brand is named at all. See AI visibility metrics.
Share of voice
Your brand's mentions as a share of all brand mentions across the same answers. See AI visibility metrics.
Average position
Where your brand appears in an answer when it appears at all. First is generally better. Treat it as a direction over many checks.
Sentiment
Whether an answer describes your brand positively, neutrally or negatively.
Citation
A source an AI answer links to or names as the basis for what it says.
Citation gap
A source that cites your competitors but never you. See AI citation gaps.
Crawlers and files
Crawler
A program that fetches web pages for a search engine or an AI company. See Can AI crawlers read your site?
robots.txt
A file at the top level of a site that tells crawlers which paths they may fetch. It is defined by RFC 9309, which says its rules are not a form of access authorization.
OAI-SearchBot
OpenAI's crawler for surfacing sites in ChatGPT's search features (OpenAI).
GPTBot
OpenAI's crawler for content that may be used to train its models (OpenAI).
ChatGPT-User
The agent that visits a page when a person asks ChatGPT something that needs it (OpenAI).
Googlebot
Google's crawler for Search. Crawling preferences set for Googlebot affect Google Search (Google).
Google-Extended
A Google product token that publishers can use to manage whether crawled content may be used for future Gemini training and grounding. Google says it does not affect inclusion in Google Search (Google).
llms.txt
A proposed Markdown file at the root of a site that lists the pages a site owner wants language models to read (llmstxt.org). See Do you need an llms.txt file?
Agency terms
Pitch
A fixed test of about 25 prompts run on a prospect and their competitors, used to show where the prospect stands before they become a client. See How to pitch AEO to a prospect.
White-label report
A report that carries an agency's own name, logo and colours instead of the tool's branding. See What to put in a client AI visibility report.
Verte Engine
An assistant inside Verte that answers questions about your results and proposes changes, such as new prompts. Nothing changes until you confirm. See the Verte Engine and AEO for agencies.
Ready to measure these? Start tracking your business or start as an agency. See current plans.